Subsea well operations often contemplate the transport of fluid, such as oil and gas, by pipe or flowlines along an ocean bottom between a subsea well producing installation and suitable storage means or supply source. Pipe or flowline connections at the subsea installation may be made by subsea divers or by subsea robots operated from suitable diving shells or other equipment. As the depth of a subsea installation increases in the attempts to produce oil from deep-sea locations, the use of divers and robots at such depths becomes more difficult and more involved. Therefore, it is desirable to use equipment which reduces to a minimum or avoids the use of subsea divers and robot equipment at very deep installations.
Prior proposed subsea wellhead installations have included preassembled wellheads and associated equipment lowered to a previously drilled wellhole and connected with the hole in well-known manner. Pipe connections made to such well installations have been made by suitable equipment to manipulate the end of a flowline to align the flowline with the pipe connector means on the wellhead installation. Problems were encountered in such alignment of a pipe end with a pipe connector means and completing a fluid-tight flowline connection to the connector means at the installation.
In some prior proposed flowline connection means, a pipe was guided vertically downwardly through the water to enter a vertically upwardly facing pivoted receptor which placed the pipe in fluid communication with an end of a flowline or other fluid communication means when the flowline was in connected locked position. (U.S. Pat. No. 3,373,807) In another prior flowline connection means, a continuous flowline on a reel was fed into the water from a pipe laying vessel and the slope and stresses of the flowline were controlled at the vessel to prevent overstressing or kinking of the flowline adjacent the sea bottom. The bottom end of the flowline was attached to a cable which was used to pull the flowline into a connecting means (U.S. Pat. No. 3,266,256). Another system for guiding a pipe end into exact position with respect to a pipe connection is shown in U.S. Pat. No. 3,592,014. Thus, in prior proposed systems for making underwater pipe connections and laying a pipe therefrom, the connections were made by diving means, by pulling or drawing a pipe into underwater equipment means for making the connection, and other equipment which placed the pipe or flowline under tension.